1. Field of the Invention
This invention relates generally to methods of generating electricity at high rates in a dynamic electrochemical junction and to fuel cells utilizing such methods.
2. Description of the Prior Art
Fuel cells using highly reactive electrochemical materials are desirable because of their large power output per unit weight and volume. Prior fuel cells have been modified to incorporate these highly reactive materials by a variety of techniques to prevent electrical shorting and to prevent direct combination of reactive chemicals.
One effective means for controlling these inherently unstable high rate reactions is to design the cathode in a dynamic mode, such as taught in Geisler, Jr. U.S. Pat. No. 3,730,776 issued May 1, 1973, the disclosure of which is hereby incorporated by reference. The system of the Geisler, Jr. patent utilizes a rotating cathode adjacent a reactive alkaline metal (e.g. sodium) anode, and a supply of aqueous electrolyte to the junction between the anode and the cathode. This design, while controlling the reaction, also decreases the rate of reaction.
Lithium is a desirable anodic material because of its high energy density. When lithium is used as an anodic material with an aqueous electrolyte, however, a thick film of LiOH forms at the anode due to the low solubility of LiOH in water. This reduces the power density delivered by the cell. The LiOH layer can be removed by a sufficient flow of water but additional water increases the weight of the cell.
Acid oxidizers may be added to the fuel cell electrolyte to increase the power output of the cell. When acid oxidizers are added to a conventional static cell incorporating highly reactive electrochemical materials such as alkali metals, however, reaction rates are difficult, if at all possible, to control.